I know what you mean about having many passwords. Here are a couple techniques I've picked up along the way...

1. BASED ON USERNAME
If you use different names in different places, you can make passwords based on the names. It is a *bad* idea to literally use the same name as the password (even backwards)- but you can write it in "leetspeak" or append a number to it (or append something else- see below).

EXAMPLE:
Username misterguy
Password m1$+3rguy

2. BASED ON SITE NAME
Same deal but based on site name:

EXAMPLE:
Site: book-of-thoth
Password +h0+h
(probably should add something to the end as a "distinguishifier")

3. BASED ON SONG LYRICS
One of my favorites is to use a song lyric that the site reminds you of. Think of it as the "theme song" for the site, then use (a) the title of the song or (b) a line from the song or (c) an acronym from a line of the song.

EXAMPLE:
iteotwawki
(the initials stand for "Its The End Of The World As We Know It")

4. BASED ON COLORS
The main color of the site:

EXAMPLE:
Username BoTty
Password bo++yblue
(on a blue site)
Password bo++yred
(on a red site)

The last one is not very useful by itself, but it's a good "distinguishifier" if you use the same name at multiple sites and just want to create minor variations on it.